Tungsten oxide is an electrochromic material that has been widely used as an electrochromic layer for assembling a new smart glass. The researchers have selected nano composite materials of tungsten oxide and niobium oxide to create such a smart glass. The substrate of the smart glass is amorphous niobium oxide, in which a tungsten oxide nanocrystal mesh-like structure is embedded. Although the two materials are electrochromic materials, their absorption spectra are different when they change color. Tungsten oxide nanocrystals absorb near infrared light, and niobium oxide absorbs visible light.

The new smart glass is transparent when not charged, both visible light and near infrared can pass through. Once voltage is applied, the tungsten oxide nanocrystal mesh structure will be charged first to change the light transmittance, thus shielding the near infrared without affecting visible light, called thermal insulation mode, which shields about 90% of the near infrared rays. If continue to charge, niobium oxide substrate will also change the light transmittance, together with visible light, shields about 80% visible light, called shading mode.